High speed printer



Patented Nov. 3, 1959 HIGH SPEED PRINTER Luciano Cignetti, Ivrea, Italy,assignor to Ing. C. Olivetti & C., S.p.A., Ivrea, Italy, a corporationof the Republic of Italy Application June 12, 1957, Serial No. 665,328

Claims priority, application Italy June 19, 1956 Claims. (Cl. 101-93)This invention relates to a high speed printer of the kind generallyusing a set of type wheels arranged sideby-side and each carrying aplurality of types, said printer being particularly useful as an outputunit for high speed data processing equipments, electronic computers andsimilar devices.

The high speed printers known heretofore of the type referred to usuallyrequire extremely costly and intricated control devices.

It is the object of the invention to eliminate this and otherdisadvantages and to provide a high speed printer which is of simplemanufacture and fast and reliable operation.

In accordance with the invention 1 provide in a high speed printer a setof type wheels frictionally driven through consecutive cycles by acontinuously rotating member associated with a clock signal generator. Ifurther provide a common zeroizing mechanism operable for arresting allthe type wheels of said set in a predetermined mutual position, controlmeans settable to operate said zeroizing mechanism and timing meanshaving a period at least as long as one cycle of said type wheels. Meansjointly controlled by said generator and said timing means are providedfor unsetting said control means to enable the type wheels to resumetheir rotation from said position in synchronism with the clock signalsgenerated by said generator.

It will thus be apparent that in the printer according to the presentinvention the type wheels normally rotate at random and only uponstarting an operating cycle they are first mutually aligned andthereupon they resume rotation in a timed relation with the clock signalgenerator, whereby the sequential steps of the type Wheels will be inperfect synchronism with the clock signals.

This and other features of the invention will become apparent from thefollowing description of a preferred embodiment thereof, taken inconjunction with the accompanying drawings in which:

Fig. l is a longitudinal sectional view showing a printer embodying theinvention;

Fig. 2 is a block diagram showing the electronic circuit for controllingthe printer shown in Fig. 1; and

Fig. 3 is a partial top plan view of the printer.

Referring now to Figs. 1 and 3, the reference numeral 1 indicates ashaft supported by the printer frame and continuously driven by a motornot shown in the drawings.

Mounted on the shaft 1 is a set of type wheels 2 arranged side-by-sideand frictionally driven by the shaft 1 in the manner described, as forexample, in applicants Italian Patent No. 510,783.

Each type wheel 2 is provided with eleven teeth 3,

bail 6 is normally disengaged from the teeth 5 by the urge of a spring 7and is operable by a solenoid 8 to engage all the teeth 5, whereby allthe wheels 2 may be arrested in a predetermined mutual position which inthe present embodiment will be their non print position.

Rockably mounted on a further pivot 45 is a set of detent levers 9, eachdetent lever being operable by a solenoid 11 against the urge of aspring 10 to engage a selected one of the teeth 3 of the correspondingtype wheel 2, whereby a selected type 4 may be set in a printingposition.

Slidably movable in a slot 13 of the printer frame schematically shownat 46 is the axle of a platen 12 whose movement toward and away fromsaid type wheels is controlled by a crank shaft 16 through a disc shapedcrank 17, a crank pin 15 and a connecting rod 14. The

shaft 16 is adapted to be frictionally driven by the motor through aslip-coupling not shown in the drawings and is normally prevented fromrotating by a detent lever 47 operable by a solenoid 18. By means of asuitable transmission the speed of the shaft 16 is half the speed of theshaft 1, whereby due to the position of the crank pin 15 on the disc 17the shaft 1 will turn through a little more than a full revolutionbefore the platen 12 upon being thrown leftwards strikes against thetype wheels 2.

Further mounted on the shaft 1 is a clock signal generator comprising atoothed magnetic disc 19 whose teeth, which are eleven like those of thetype wheels 2, co operate with a magnetic pick-up head 20. Thereluctance variation which occurs as the teeth of the disc 19 passbetween the pole pieces of the head 20 induces therein a voltage whichis then amplified and shaped at 21 to ob tain a suitable clock signal Sin a manner well known in the art. By way of example, a suitableamplifying and shaping circuit is shown in the United States Patent2,609,143, Fig. 4. The frequency of the clock signals S is determinedboth by the number of revolutions of the shaft 1 and the teeth number ofthe disc 19. In the present embodiment eleven clock signals S aregenerated at each revolution of the shaft 1.

Referring now to Fig. 2, an electronic circuit is shown which is timedby the clock signals S to suitably control the energization of thesolenoids 8, 11 and 18. This circuit makes use of conventionalcomponents, such as andgates, one-shot multivibrators, flip-flops,switches, delay units and counters, which are well known in the art, as

for example, from the book Electronics Experimental Techniques byWilliam C. Elmore and Matthew Sands, McGraw-Hill, 1949, and thereforewill not be described hereinafter in detail.

As shown in Fig. 2, the circuit comprises a first part A controlling thesequence of the zeroizing, selecting and printing phases which form anoperating cycle of the printer, and a second part B controlling theselective arrest of the type wheels 2 according to an item to beprinted.

To initiate a printing cycle a start signal is applied in a known way tothe input terminal 22. Through a condenser 23 this signal trips over atiming means including a one-shot or univibrator 24 of the typedescribed in the cited book with reference to page 87 and Figs. 2.33.The one-shot 24 in turn through a condenser 25 sets a control means suchas a flip-flop 26 to its state II thus triggering a switch 27 adapted tocause energization of the solenoid 8.

Therefore, the solenoid 8 moves the comb bail 6 to place the lugs 6'into the path of the zeroizing teeth 5. Since during the next precedingprinting cycle, as will be seen hereinafter, the type Wheel 2 had beenangularly moved with respect to the shaft 1 according to the individualtype selected in said cycle, the zeroizing teeth I 5.. Will now contactthe corresponding lugs 6 of the bail 6 in various instants of onerevolution of the shaft 1, whereby the type wheels 2 will be arrested intheir non print position, provided the solenoid is held energized duringat=leastone full revolution of the shaft 1. 1

To thisend'the flip-flop 26 will not be reset to its state I untilreturn of'theone-shot 24-to its initial state, the period of theone-shot24 being a little longer than the duration. of a full revolutionof theshaft 1.

More. particularly, the one-shot 24 upon returning to its initial. statesends a signal through a condenser 28 to a flip-flop 29 which will thusbe set to its state II. An and-gate 3%,havingan input supplied by theclock signals S,-is thus opened and the first clock signal, outgoingtherefrom trips over a further one-shot 31 similar to the oneshot .24and included in said timing means, the period of said one-shot 311beinga-little longer as well than one revolution of theshaft 1.-

Upon trip-over-the. one-shot'31' opens an and-gate 32 which also has aninput supplied by the clock signals S. Thefirst signal outgoing fromsaid and-gate 32 resets both theflip-flop 26i-and, through a delay'unit33, the flipfiop 29.

The flip-flop 26 on being reset to the state I turns off the switch 27thus discontinuing the energization of the solenoid 8; The comb bail 6is therefore restored by its spring 7 and the wheels 2.are now releasedto resume rotation bodily with the shaft l-from said non print"position. It will thus be apparent that, since the release of the wheels2 was timed with a certain one of the clock signals S, a timed relationhas been established between the generator and the rotation of thewheels 2, whereby the sequential steps thereof will be in perfectsynchronism with the clock signals.

Upon being reset to the state I the flip-flop-26 further triggersthrough a condenser 34a switch 35 controlling energization'of thesolenoid 18. The switch 35 may be, by way of example, of the thyratrontype shown in the United States Patent 2,692,551, Fig; 5. On beingenergized the solenoid 18releases the disk 17 thus allowing the shaft 16to start rotation. At the end of-rone revolution the shaft 16 is adaptedbyiknown means to operate a switch 36, 36 36 (Fig.2) inserted in thesupply circuits of the solenoid 18 and the solenoids 11 11,,, to the endof transitorily opening said circuits.

During the timeelapsing from the release of the'disc 17 to the strikingof the platen 12 against the wheels .2-

the part Bofv the electronic'circuit performs the selection of thecharacters to be printed. Thispart comprises as many identicallcircuitarms as are the type wheels 2- whichiare supposed to be arranged in ndenominational orders. Corresponding to each denominational order isacounter 37 digit of an item to be printed is set up and then a sequenceof impulses is entereduntil the counter is filled up, such a counter:being usually referred to as predetermined counter. This ..item-comesfrom astore 38 which for instance may beof the well known typeofmain orauxiliary store used in electronic computers. Each counter 37 is of thetype formed, as for example, of a chain'of flip-flops and shown in thecited book, pages 209 to 212 and 'Fig. 4.3.

Upon trip-over the one-shot 31 opens both the andgate 32, as describedabove, and a set of and-gates 39, thus allowing the signals S to enterthe selecting circuit and to initiate type selection, one gate 39 beingprovided for each denominational circuit arm. The output signals ofeachgate 39 pass a delay unit 40 and a condenser 41. and'sequentiallyenterthe corresponding counter 37, wherein they are added to the digitpreviously setup. Upon: beingiilled up each counter 37 is automaticallycleared thereby'generating an output pulse which through a condenser 42triggers a switch 43. The latter switch maybe of the above mentionedthyratron type and causes energization of the corresponding solenoid'11.. At the 37 wherein first the corresponding same time the counter 37remains locked by known means until a new item is set up therein.

The present combination of predetermined counters, condensers, thyratronswitches and solenoids is similar to the combination illustrated in theUnited States Patent 2,692,551 with reference-to Figa- 1 and will thusnot be described in detail.

It will thus be apparent that each type wheel 2 will be 'arre'stedup'onhaving advanced anumben of-steps con-- ditioned by-the-digi-t set-upinthe corresponding counter. More particularly, if a digit x to be printedis setup in a counter-37,'the numberrof signals S required to fill upthe counter and therefore the number of steps made by the corresponding'type-wheel 2" will be equal, in the present embodiment, to thetencomplement of x, provided the types 4 are arranged as shown in Fig. 1.

The selecting phase ends when the one-shot 31 returns to its initialstateat-the endofits period, thereby shuttingtthe and-gates 39. Itshould be remarked that during the time the one-shot 31-remains trippedover the and-,gate.32=remains open, whereby the output signalsof:the:latter gate1may;preventtheflip-flop 26 from being set to itsstate II by a start signal eventually applied to the input 22. beforecompletion of the cycle previously initiated;

It has been stated above that upon completion of the selectingnphase theplaten 12. strikes against the type wheels 2 thus printing the selecteditem.v

Upon completion of one revolution the shaft 16 operates the switch 36which opens the supply circuits of the solenoids18 and 11 thusdeenergizing. same. whereby the shaft 16wis arrested and the wheels 2are released and'start again rotation :bodily with the shaft 1.

To. ensure: a reliable and correct operation of the printer,suitabledelay units 40 are provided havinga delay adjustable at will. Inthe, drawings a plurality of delay units '40is shown, onedelay unitbeing provided for each denominational; circuit arm, but a'single delayunit common toall said arms may be" provided as well.

Briefly," a printer according to the invention operates as follows;After having, set up; an item in the counters 37 37, a start signal isapplied to the input terminal 22. This signal trips 'over the one-shot24 which in turn sets the flip-flop 26 to its-state II. The solenoid8'is thus energized and moves the bail 6 into engagement with thezeroizinggteeth 5. The type wheels:2,which had been angularly positionedwith respect to the shaft 1 according to the types selected -in' thenext preceding cycle are,v therefore, aligned in their non printposition.

At theend of its period the one-shot 24 sets the flipfiop 29 to .itsstate II, whereby the first signal S thereafter generated will trip overthe one shot 31. The latter allows the-same'signal S to resettheflip-flop 26 thus bothdeenergizing the solenoid 8, whereby the typewheels 2 aligned as above start again'rotation, and energizing-thesolenoid 1S,- whereby the-shaft 16 is started.

The one-shot 31 further enables the andgates 39 to allow-the signals Sto'enter the-counters-37. When-any counter-37 fills up it"generates anoutput pulse which energizes the correspondingsolenoid 11, whereby theas sociated type wheel 2 will be arrested in the selected position;

Within one revolution of the shaft 1 allthe type wheels 2 are arrestedaccording to the item set up in the counters 37, said item beingthereupon printed by the platen 12.

Finally, atthe end'of its period the one-shot 31 shuts the gates 32and'39,'while at the end of one revolution of the shaft 16 the switch 36causes the shaft 16 to be stopped and the detent levers 9 to release thetype wheels 2. The printer isthus restored to normal and is adaptedtoinitiate anew operating cycle.

It willibe apparent'that the'zeroizing and the selecting phasesoccurring wi'thin an operating cycle are timed by the periods of -theone-shots 24 and 31,: respectively, and that the printing :phaseisdetermined by the striking of the platen 12 against the type wheels 2after a little more than half a revolution of the shaft 16.

While the invention has been described primarily in terms of controllinga high speed printer having the simplest embodiment of frictionallydriven type wheels, it should nevertheless be understood that the typewheels may be actuated by other embodiments of non-positive generallyfrictional drives, such as hydraulic or pneumatic joints, pawl andstar-wheel joints and the like known in the art. The term frictionallydriven as used in the appended claims should, therefore, be intended asbroad enough as to embrace said other drives.

While I have disclosed and described herein a presently preferredembodiment of the invention, it should nevertheless be understood thatthe same is susceptible of various modifications and changes by thoseskilled in the art.

I claim:

1. In a high speed printer, a set of type wheels, a continuouslyrotating member for frictionally driving said wheels through consecutivecycles, a clock signal generator associated with said member, a normallyineffective common zeroizing mechanism operable for arresting all thetype wheels of said set in a predetermined mutual position, controlmeans settable irrespective of the instantaneous angular position ofsaid rotating member to operate said zeroizing mechanism, timing meanshaving a period at least as long as one cycle of said type wheels, andmeans jointly controlled by said generator and said timing means forunsetting said control means to enable said type wheels to resume theirrotation from said position in synchronism with the clock signalsgenerated by said generator.

2. In a high speed printer, a set of type wheels, a continuouslyrotating member for frictionally driving said wheels through consecutivecycles, a clock signal generator associated with said member, a normallyineffective common zeroizing mechanism operable for arresting all thetype wheels of said set in a predetermined mutual position, normallyinefiective individual arresting means operable for selectivelyarresting said type wheels according to an item to be printed, controlmeans settable irrespective of the instantaneous angular position ofsaid rotating member to operate said zeroizing mechanism, timing meanshaving a period at least as long as one cycle of said type wheels, andmeans jointly controlled by said generator and said timing means forunsetting said control means to enable said type wheels to resume theirrotation from said position and for rendering said individual arrestingmeans efiective.

3. In a high speed printer, a set of type wheels, a continuouslyrotating member for frictionally driving said wheels through consecutivecycles, a clock signal generator associated with said member, a commonzeroizing mechanism operable for arresting all the type wheels of saidset in a predetermined mutual position, a one-shot multivibrator havinga period at least as long as one cycle of said type wheels, controlmeans settable by said multivibrator upon trip-over to operate saidzeroizing mechanism, and means jointly controlled by said generator andsaid multivibrator upon return of the latter to its initial state forunsetting said control means to enable said type wheels to resume theirrotation from said position.

4. in a high speed printer, a set of type wheels, a continuouslyrotating member for frictionally driving said wheels through consecutivecycles, a clock signal generator associated with said member, a commonzeroizing mechanism operable for arresting all the type wheels of saidset in a predetermined mutual position, normally ineffective individualarresting means operable for selectively arresting said type wheelsaccording .to an item to be printed, a first and a second one-shotmultivibrator each having a period at least as long as one cycle of saidtype wheels, said second multivibrator be ing controlled by said firstmultivibrator to be tripped over substantially on the return of saidfirst multivibrator to its initial state, control means settable by saidfirst multivibrator upon trip-over to operate said zeroizing mechanism,and means jointly controlled by said generator and said secondmultivibrator upon trip-over of the latter for unsetting said controlmeans to enable said type wheels to resume their rotation from saidposition and for rendering said individual arresting means effective.

5. In a high speed printer, a set of type wheels, a continuouslyrotating member for frictionally driving said wheels through consecutivecycles, a clock signal generator associated with said member, a commonzeroizing mechanism operable for arresting all the type Wheels of saidset in a predetermined mutual position, normally inefiective individualarresting means operable for selectively arresting said type wheelsaccording to an item to be printed, a first and a second one-shotmultivibrator each having a period at least as long as one cycle of saidtype wheels, said second multivibr-ator being controlled by said firstmultivibrator to be tripped over substantially on the return of saidfirst multivibrator to its initial state, control means settable by saidfirst multivibrator upon trip-over to operate said zeroizing mechanism,means jointly controlled by said generator and said second multivibratorupon trip-over of the latter for unsetting said control means to enablesaid type wheels to resume their rotation from said position, and a setof predetermined counters jointly controlled by said generator and saidsecond multivibrator for rendering said individual arresting meansefiective upon the tripover of said second multivibrator.

References Cited in the file of this; atent UNITED STATES PATENTS1,675,969 Bull July 3, 1928 2,133,865 La Boiteaux Oct. 18, 19382,157,035 Torkelson May 2, 1939 2,566,944 Last Sept. 4, 1951 2,796,830Hilton June 25, 1957 2,799,221 Olivetti July 16, 1957

